The present invention relates to a method for providing vacuum of a brake actuation device of a motor vehicle brake system comprising a pneumatic brake booster, the interior of which is subdivided into at least one vacuum chamber and one working chamber, a master brake cylinder and a pneumatic motor-and-pump assembly for providing the vacuum in the vacuum chamber, which comprises a vacuum pump and a motor driving the vacuum pump, wherein a vacuum level in the vacuum chamber or a difference in pressure between the vacuum chamber and the working chamber is sensed using a sensor, and the motor-and-pump assembly is enabled by an electronic control unit when the vacuum falls below a first defined bottom vacuum level in the vacuum chamber, and is disabled when a second defined top vacuum level is reached.
A method of this type is e.g. disclosed in DE 199 29 880 A1, wherein the vacuum pump is additionally activated in dependence on operating conditions of the driving unit. It is, however, considered disadvantageous that the activation and the operation of the vacuum pump in various driving conditions cause significant noise, which the driver of the vehicle feels as disturbing.
In view of the above, an object of the invention involves offering a method to solve the problem of minimizing the disturbing noise that develops due to the motor-and-pump assembly or of adapting it to driving conditions of the vehicle.